diff --git a/README.md b/README.md
index 7da706d..088ae2b 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ PHP class for [two-factor (or multi-factor) authentication](http://en.wikipedia.
 
 * Tested on PHP 5.3, 5.4, 5.5 and 5.6
 * [cURL](http://php.net/manual/en/book.curl.php) when using the provided `GoogleQRCodeProvider` (default), `QRServerProvider` or `QRicketProvider` but you can also provide your own QR-code provider.
-
+* [MCrypt](http://php.net/manual/en/book.mcrypt.php), [OpenSSL](http://php.net/manual/en/book.openssl.php) or [Hash](http://php.net/manual/en/book.hash.php) depending on which built-in RNG you use (TwoFactorAuth) will try to 'autodetect' and use the best available).
 
 ## Usage